So my metro applications stopped working, including start button and notifications button. When i try to open one it shows on second then it closes itself. I checked event viewer, and there were a lot of errors, they always appear when i try to open an application. Example when I press start button:

Activation of the app Microsoft.Windows.ShellExperienceHost_cw5n1h2txyewy!App for the Windows.Launch contract failed with error: The app didn't start..

I know what might have caused this error, i done a stupid thing and i used a program Unlocker 1.9.2 and i unlocked Windows folder (That program is used when you want to unlock a file to delete it ) So i don't know what problems i made, is reinstalling windows only solution?

I assume you have attempted to restart your computer? What folder did you used this program on specifically?
– RamhoundDec 1 '15 at 22:12

look in the eventlog and post the error messages that you see there
– magicandre1981Dec 2 '15 at 5:30

@Ramhound i restarted it few times and it still didn't work ( just turned it on and off , not that restart for deleting everything ), and i used that program on windows system folder (C:/windows/ ) and its all subfolders and files.
– Warix3Dec 2 '15 at 14:40